This invention relates to novel 6,7,8,9-tetrahydronaphthol[1,2-b]furan-8-amine derivatives, to therapeutically acceptable acid addition salts thereof, to processes for their preparation, to methods of using the derivatives and to pharmaceutical compositions of the derivatives. These derivatives exhibit dopamine-receptor stimulating activity in a mammal. Thus, they can be useful for treating hyperprolactinemia, galactorrhea, amenorrhea, impotence, Parkinsonism, diabetes, acromegaly, hypertension and other central nervous system disorders which respond to dopamine-receptor simulation.
Although the naphtho[1,2-b]furan derivatives of this invention represent a novel tricyclic ring system, a number of benzindole derivatives are known and described, for example, L. B. Shagalov et al., Chem. Abstr., 91, 56747 v (1979) for Khim. Geterotsikl. Soedin., (3), 360 (1979); L. B. Shagalov et al., Chem. Abstr., 89, 146703 r (1978) for Khim. Geterotsikl. Soedin., (5), 634 (1978); Derwent Publications Ltd., Farmdoc 46000U for Netherland Patent No. 7,300,871, published July 30, 1973; and Derwent Publications Ltd., Farmdoc 24087B for German Offenlegenshift No. 2,740,836, published Mar. 22, 1979. The compounds described in the above reports have a benzindole ring system as contrasted to the naphtho[1,2-b]furan derivatives of this invention.
N. J. Bach and E. C. Kornfield, U.S. Pat. No. 4,110,339, Aug. 29, 1978 disclose tricyclic benzo[c]pyrroles which are dopamine agonists. These latter compounds are distinguished most readily from the compounds of this invention by having a fused tricyclic ring system with a nitrogen.